This invention relates to microfabrication. In particular, it relates to the microfabrication of a structure for a Microelectromechanical Systems (MEMS) device.
Microfabrication techniques used to fabricate MEMS devices generally involve the deposition of one or more layers on a substrate and the subsequent patterning of the layers to produce useful structures. One technique for patterning a layer involves the use of photolithography. With photolithography a photographic definition of a desired pattern on a photo or optical mask is used to impart the pattern onto a surface of the layer. When manufacturing a MEMS device usually several masking steps are required, each masking step adding to the cost of the device. Accordingly, it is desirable to reduce the number of masking steps required during fabrication of a MEMS device.
According to one aspect of the invention there is provided a microfabrication process comprising depositing a first layer on a substrate; patterning the first layer; depositing a second layer on the first layer; and patterning the second layer using the first layer as a photomask.